Method of making screen plates



Oct. 25, 1938. w. RAISCH 2,134,146

METHOD OF MAKING SCREEN PLATES Filed May 5, 1955 2 Sheets-Sheet 1INVENTORY WilliamRal'sck ATTORNEY Patented Oct. 25, 1938 'METHOD OFMAKING SCREEN PLATES William Raisch, Forest Hills, N. Y., assignor toMunicipal Sanitary Service Corporation, New York, N. Y., a corporationof New York Application May 3, 1935, Serial No. 19,655

1 Claim.

My invention relates to screens and more particularly to screen platesand methods of making the same.

Heretofore certain screens for removing solids from sewage and otherliquids have been formed of one or more sections, which may be in theform of screen plates, each provided with a plurality of narrow slotsrelatively close together. Such a screen plate has commonly been formedfrom a single or integral piece of flat metal by milling the slots fromthe bottom side of the plate. This method of forming the slots wouldcause the end walls to be curved in conformity with the shape of themilling cutter whereby the slots would be shorter on the top side of thebar than on the bottom and the effective screening area of the screenplate Would be reduced to a very considerable extent. Furthermore, trapswould be formed in the curved and under cut ends of the milled slots andwould tend to collect solid matter and thereby further reduce theeffective screening area of the plate. ,A screen section of another typehas heretofore been made of a plurality of bars placed side by side andsecured in proper spaced relation either temporarily or permanently asby welding them to suitable transverse members. In this form of screensection it is difficult to produce accurate spacing of the bars.

An important object of the present invention is to provide a novel andadvantageous screen plate whereby the above and other disadvantages willbe obviated. Another important object is to provide a novel andadvantageous method of 35 making such screen plates.

In carrying out the present invention, the blank for the screen sectionmay be in the form of a plate which may be straight or curved accordingto the use to which the screen section is to be 40 put. After securingto the back of the blank one or more reinforcing members in a suitablemanner, as by welding, the format on of the slots is started by cuttingdeep grooves, as by milling, in the face of the plate. Such grooves arecut nearly to the back face of the plate and preferably from edge toedge thereof so that upon removing metal at the back face, as bygrinding, between the reinforcing members at the back of the plate theslots will be opened completely 50 through the plate and will beseparated by accurately spaced bars. Ordinarily such slots andconsequently the intervening bars will be parallel but for some kinds ofscreens the slots may be curved and uniformly spaced.

I: The completed screen plates may be secured in position in anysuitable manner but preferably by using some of the reinforcements atthe back of the plates for such purposes, for example, by forming someof such reinforcements as sleeves through which supporting rods may bepassed. 5 In a prefered form, each screen plate comprises in a unitaryor integral structure a plurality of bars extending from edge to edge ofthe plate and secured together at their backs by reinforcing membersextending transversely thereof. Al- 10 though the bars are not separatedentirely at the back of the screen plate there are deep grooves at theface side of the plate so that it will be relatively easy to clean thescreen by suitable means moving along the face thereof and pro- 15jecting into the grooves and slots.

Other objects, features and advantages will appear upon consideration ofthe following description and of the drawings, in which Fig. l is aperspective view of a blank plate and so the parts to be securedthereto;

Fig. 2 is a side elevation of a plate with the other parts securedthereto;

Fig. 3 is a perspective view illustrating the formation of slots at thefront face of the plate; 25

Fig. 4 is a sectional view taken along the line 44 of Fig. 3;

Fig. 5 is a perspective view illustrating the opening of the slots atthe back face of the plate;

Fig. 6 is a perspective view of the completed screen plate;

Fig. 7 is a section taken along the line 1-1 of Fig. 6; and

Fig. 8 is a section taken along the line 88 of Fig. 7.

Referring to the drawings, reference numeral l0 designates a plate orblank II! to which are to be attached a central reinforcing member orbar II and reinforcing and attaching members l2, which may be in theform of sleeves flattened at one side for engagement with the backsurface of plate l0. As illustrated in Fig. 2, the members II and [2 maybe secured to the plate Ill, as by welding, so as to form asubstantially integral structure. After the parts have been assembled asshown in Fig. 2, deep grooves I3 are cut in the front face of the plateIn leaving only thin connections M at the back of the plate. Asillustrated in Fig. 3 the cutting of the grooves may be efiected by amilling tool I 5 and the milling may be effected while the plate is heldbetween bars l6 which may be used as part of the complete screen, thesebars being carefully machined into proper straight or curved shape inaccordance with the final form of the screen. The plate may be held inposition between the bars I6 by rods I9 passing through the sleeves l2and through suitable openings 20 in bars l6 (Fig. 3).

After completion of the slot forming operation illustrated in Fig. 3,the back surface of the plate In is removed,-as by use of a grindingtool ll, so as to open up the slots I3 at the back face, and form bars2| which are connected by means including members II and I2. Thefinished screen plate I8 thus formed may be supported in the finalscreen structure by means of the same I or similar rods l9 passingthrough the sleeves I2 1 and through suitable openings 20 in the same orlike bars l6. Preferably the grooves l3 are cut from edge to edge ofeach plate and the plate is so ground that the bars are separated attheir ends.

It should be understood that various changes may be made in certainfeatures and that certain features may be used without others withoutdeparting from the true scope and spirit of the invention.

Having thus described my invention, I claim: The method of making ascreen plate consisting over the major part of its area of a single setof integrally united parallel bars whose depth

